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Instream restoration: its effects on lateral stream–subsurface water exchange in urban and agricultural streams in Southern Ontario
Author(s) -
Kasahara Tamao,
Hill Alan R.
Publication year - 2007
Publication title -
river research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.679
H-Index - 94
eISSN - 1535-1467
pISSN - 1535-1459
DOI - 10.1002/rra.1010
Subject(s) - meander (mathematics) , stream restoration , streams , subsurface flow , hyporheic zone , hydrology (agriculture) , floodplain , channel (broadcasting) , geology , environmental science , substrate (aquarium) , hydraulic conductivity , surface water , groundwater , soil science , geotechnical engineering , soil water , environmental engineering , computer network , ecology , oceanography , geometry , mathematics , electrical engineering , engineering , computer science , biology
Instream restoration strategies do not generally consider the subsurface environment. The study of recently restored stream reaches can provide an opportunity to assess the impacts of restoration on surface–subsurface exchange. In this study, lateral hyporheic zones occurring in a constructed gravel bar and re‐meandered stream reach were examined, using hydrometric data in combination with differences in background conservative ion and tracer injection experiments. Both the constructed gravel bar and the meander bends induced lateral hyporheic exchange flow. In the gravel bar, lateral hyporheic exchange increased after a riffle‐pool sequence was constructed in the channel adjacent to the bar. The substrate in the meander bends had low saturated hydraulic conductivity, and the stream–subsurface exchange was limited despite the large change in channel configuration. These results suggest that to enhance and maintain stream–subsurface water exchanges, restoration projects that modify horizontal geometry should involve construction of vertical morphologic features, and where floodplain sediments are fine‐grained, the addition of coarse sediments should also be incorporated in the design. Copyright © 2007 John Wiley & Sons, Ltd.